To quote https://wiki.creativecommons.org/wiki/Marking_Works_Technical
> Included Objects
> Objects included in web pages, such as images, should be annotated as above
> within their "host" web pages. Ideally all included objects should also embed
> object format native notice and metadata as described below, but this is only
> crucial for objects where the publisher intends for or is concerned about
> distribution outside the context of the "host" web page.
> Metadata about include objects that have their own URIs should be qualified
> with about, as rel="license" without an about attribute makes a statement
> about the current document (which is the "host" web page). Example:
> Photo licensed under <a about="http://example.com/some-image.png"
> href="https://creativecommons.org/licenses/by/4.0/">cc by 4.0</a>.
Perhaps this could be added to Commons as a mediawiki extension for Google to
start picking it up and showing the licensing information in its search
results. Currently Commons shows link tags with rel="license" attribute but
they specify the whole page license, like they should.
Discovery mailing list